evolve 0.4.0

A generic, composable genetic algorithm framework for Rust
Documentation 
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157

use crate::{
    core::{context::Context, offspring::Offspring, population::Population, state::State},
    operators::GeneticOperator,
};

/// Chains operators sequentially, feeding each operator's output as input to the next.
///
/// Accepts a tuple of up to 16 operators. The first operator receives the current
/// state's population; each subsequent operator receives the output of the previous one.
///
/// # Examples
///
/// ```
/// use evolve::operators::sequential::combinator::Pipeline;
/// use evolve::operators::sequential::crossover::SinglePoint;
/// use evolve::operators::sequential::mutation::RandomReset;
/// use evolve::operators::sequential::selection::Tournament;
/// use std::num::NonZero;
///
/// // Select → Crossover → Mutate
/// let op = Pipeline::new((
///     Tournament::new(NonZero::new(3).unwrap()),
///     SinglePoint::<u8>::new(),
///     RandomReset::<u8>::new(),
/// ));
/// ```
#[derive(Debug, Clone)]
pub struct Pipeline<O: ?Sized>(O);

impl<O> Pipeline<O> {
    /// Creates a new `Pipeline` from a tuple of operators.
    pub fn new(operators: O) -> Self {
        Self(operators)
    }
}

macro_rules! impl_genetic_pipeline {
    () => {};
    // Single operator (no chaining needed)
    ($first:ident) => {
        impl<G, F, Fe, R, C, $first> GeneticOperator<G, F, Fe, R, C>
            for Pipeline<($first,)>
        where
            $first: GeneticOperator<G, F, Fe, R, C>,
        {
            fn apply(
                &self,
                state: &State<G, F>,
                ctx: &mut Context<Fe, R, C>,
            ) -> Offspring<G, F> {
                self.0.0.apply(state, ctx)
            }
        }
    };
    // 2+ operators
    ($first:ident, $($rest:ident),+) => {
        impl<G, F, Fe, R, C, $first, $($rest),*> GeneticOperator<G, F, Fe, R, C>
            for Pipeline<($first, $($rest,)*)>
        where
            $first: GeneticOperator<G, F, Fe, R, C>,
            $($rest: GeneticOperator<G, F, Fe, R, C>),*,
        {
            fn apply(
                &self,
                state: &State<G, F>,
                ctx: &mut Context<Fe, R, C>,
            ) -> Offspring<G, F> {
                #[allow(non_snake_case)]
                let ($first, $($rest,)*) = &self.0;

                // Step 1: apply first operator
                let mut current_population = match $first.apply(state, ctx) {
                    Offspring::Single(ind) => {
                        let mut p = Population::new();
                        p.add(ind);
                        p
                    }
                    Offspring::Multiple(p) => p,
                };

                // Step 2: apply remaining operators
                $(
                    let next_state = state.with_population(current_population);

                    current_population = match $rest.transform(next_state, ctx) {
                        Offspring::Single(ind) => {
                            let mut p = Population::new();
                            p.add(ind);
                            p
                        }
                        Offspring::Multiple(p) => p,
                    };
                )*

                Offspring::Multiple(current_population)
            }
        }

        impl_genetic_pipeline!($($rest),*);
    };
}

impl_genetic_pipeline!(
    T1, T2, T3, T4, T5, T6, T7, T8, T9, T10, T11, T12, T13, T14, T15, T16
);

impl<G, F, Fe, R, C, O> GeneticOperator<G, F, Fe, R, C> for Pipeline<[O]>
where
    O: GeneticOperator<G, F, Fe, R, C>,
{
    fn apply(&self, state: &State<G, F>, ctx: &mut Context<Fe, R, C>) -> Offspring<G, F> {
        // this is bad, assuming its safe to just index
        let mut offspring = self.0[0].apply(state, ctx);

        for operator in &self.0[1..] {
            let population = offspring.into_population();
            let owned_state = state.with_population(population);
            offspring = operator.transform(owned_state, ctx);
        }

        offspring
    }
}

impl<G, F, Fe, R, C, O> GeneticOperator<G, F, Fe, R, C> for Pipeline<Vec<O>>
where
    O: GeneticOperator<G, F, Fe, R, C>,
{
    fn apply(&self, state: &State<G, F>, ctx: &mut Context<Fe, R, C>) -> Offspring<G, F> {
        let mut offspring = self.0[0].apply(state, ctx);

        for operator in &self.0[1..] {
            let population = offspring.into_population();
            let owned_state = state.with_population(population);
            offspring = operator.transform(owned_state, ctx);
        }

        offspring
    }
}

impl<G, F, Fe, R, C, O> GeneticOperator<G, F, Fe, R, C> for Pipeline<Box<[O]>>
where
    O: GeneticOperator<G, F, Fe, R, C>,
{
    fn apply(&self, state: &State<G, F>, ctx: &mut Context<Fe, R, C>) -> Offspring<G, F> {
        let mut offspring = self.0[0].apply(state, ctx);

        for operator in &self.0[1..] {
            let population = offspring.into_population();
            let owned_state = state.with_population(population);
            offspring = operator.transform(owned_state, ctx);
        }

        offspring
    }
}